Automatic clutch device



Sept. l2, 1933. E. c. HATCHER AUTOMATIC CLUTCH DEVICE Filed 00T.. 29, i931 Patented Sept.V 12, 1933* UNITED STATES *AUTOMATIC CLUTCH DEVICE Ernest Charles Hatcher, Northwood, England, as-

signor to'J. Stone & Company Limited,v Dept-'- ford, England, a company of Great Britain.

. VApplication October 29, 1931, Serial No.v 571,850, Y and inGreat Britain November'ztl,` 1930 `s Claims'. (01.,7192-4105) u This invention concerns improvements in and V relatingto centrifugal clutch devices for use in transmission gearing particularly such gearing as employed in association'with the running' axles of vehicles.` The invention relates to improvements in centrifugal clutch devices of the kind wherein the centrifugal clutch members are subjectedrto a camming or wedging action by the driving member when they grip the driven member,- the object being to'obtain a driving grip which is greater and prompter in action than that obtained by `centrifugaleffects alone.` Such a clutch and a mode of use thereof are described, for instance, in applicants Patentv No.` 1,857,020,` dateert/ray s, 1932. Y

For some types of drive, for example, in the driving of certain auxiliary apparatus from the axles of vehicles .it is undesirable that `a sharp jerk should be given to the driven portion ofthe transmission gearing at the moment when the wed'ging or camming actionreinforces the centrifugal clutching effect. Anobject of the pres`` ent invention is to obviatel the possibility of such op'osesA ofv the present invention this movement a ljerk without sacrificing any ofthe substantialadvantages of the type of centrifugal clutch referredto. According-,to the present invention, therefore, provision is madera-forav comparatively gentle transition or gradual change from the ini;` tial clutching stage in whichcentrifugalaction alone is involved and the final clutching fcondi-V tion in which the centrifugal action is assisted by wedging or camming action. To this end use is made of means for resiliently resistingv the camming or wedging movement. With the'arrangement described' in the above numbered pat- Y ent, the wedging or camming action Vis brought about by slight 'circumferential movement or retardati'on of the clutch shoesfwhen they come into contactwith the drivenmember;v 'For the Lpur maybe resisted Aby spring means, a counteract ing centrifugal effector the like, theamount and nature of the resistance beingdesignedto afford the desiredlgive or resilience at the m07 ment whenlthe clutch automatically 'engagea Reference will now bekmade to various embodifA ments of the invention illustrated by waymof ex.

ample. in the accompanying drawing Vandintended more particularly for use yin conjunctionfwith clutches constructed and employed in the mark v ner described inA the patent` abovereferred to'.

VIn said drawing:

. section respectively of-on'ez embodiment, L t

vFiguresv 3 vand 4 cross-sections of alternative embodiments. f

Figures `5 vand 6 part sectional rend andside elevations lof! a modied arrangement.

1 In the` arrangement shown; in Figures 1 and 2, each shallow clutchshoe` lis providedwith a circumferential slot 2 for the accommodation of a compression spring 3 Which, when at its nor-Y mal extension, Vprojects beyond the cam portions 4 of the shoe into contact with stops '5.which are carriedby the driving member 6Qfast on the ,driving shaft '7. Each spring r3 is anchored centrally of its `length or (as shown) 'isdivided into two parts separated by astop l8 formed on the shoe 1 in the slot 2. Said springlparts 3 are covered, in the slot 2, by the clutch-shoe facing or pad 10 which is made of friction material for Y gripping against theinner face of the drum 11 Below the cut-in speedv memberd `With a reversible clutchLthe shoe 1l is maintained rmidway between the camming or; wedging surfaces 13 provided on said driving member 6 for the two directions of rotation; On thecut-in speed being `attained the centrifugal force'acting on the shoe 1` will have brought the shoe-facing 10 into Contact with thedriven mem-L ber 11 which, tending to retard the shoe, will cause the trailing spring-part 3 to be compressed betw'eenthe following stopon the driving member 6 and the stop 8 on the shoe 1. The `spring is not made suiciently `'strong to prevent thecooperating cam surfaces 4, V13 onfthe shoe 1 `and driving member 6 from entering into engagement to'assist the centrifugal action but is merely made Y stops 5but free tofslide through the washers sor 15 `intoa slot in the stopmS'. In any case the arrangement-must not be such' as to interfere with the proper action of any normal spring loading j (not'shown) provided to resist the outwardrmovementwof the centrifugal elements of the clutch. It will `be appreciatedthat the springs 3 ,will

s themselves'facilitate l disengagement of the shoeV from `the driven member. i

- Alternatively the'driving member i6 may be providedl with buffer devices Whose resistance must be overcome before full wedging engagement between the shoesl and said driving mem'- ber takes place. Such buffer-devices may, as illustrated in Figure 3, takethe form of C-shaped springs 16 secured in transverse slots .17 in the cam elevations 13 on the driving member 6. The l C-shaped springs ,16. are designed so thatl ltheir limbs, normally extending outsidesaid `slots 17',

are adapted tobe forced thereinto by the movement of the clutch shoes 1 when retarded by' the driven member 11. Instead of being accom-f modated in the slots 17, the springs 16 might be mounted at one'or both ends of the driving member.

In another modification the wedging engagement withfthe driving member 6 is provided by ay further .centrifugal element which must be moved inwardly against the cen.

trifugal force acting thereon lbefore suchl en-A gagement can take Place. As shown in Figure 4, such' further' centrifugal' element takes. theform of a weight 16 mounted so as .to lb efcapable i Cil of slidingfradially .in la slot 19 in the Idriving member One end. of said. weight lfisl ar'- ranged tofproject intoaid-"contact with a came shaped .slot ZOinthe shoe 1, the camfbei'ng designed to .move 'the 'weight' inwardly -whe'the shoe 1 is] given a "circumferential retardation upon .its engagement with the driven member 11'.. The effect is the same as vwith the springs previously. described; Obviously combinations@ of the means referred/te could be utilized in""car" rying the'.inventien.irito'eiiectiVv Y u y For .certain'purpos'es for. instance in the drivingof generatorssupplyig heating current,'it

rnayfiiie"A desirable` to make the Hclutch capable of being permanently disengaged thefdrive is not required, inthe iistanee given, say.,. during ywarm Weather. To enable thi'sf to s be `done the' 'clutch shoes 1 may eachbel'provided with/a proiectionrl (Figures 5 and ,6)l which,v when saidshees'are' u'nexpanded,f 'can .be engagedby a klocking 'device mounted on alfterminalf'fiange 22fon. the drivingV member 6. ,.."Ihisdevce con;A

`Vshown inthe 'preceding guresmf t projecting. through an arcuate'k lslot'Zinl flange.y By moving the screw I to one end'loffthe s lot ,.`th'e' abutment finger .can be caused to enygage'"over the"projection 21 (Figure 5)' thereby preventing?centrifugal expansion of the shoeV l and renderingthe'.clutchinoperative; When at the'otlier.endbffsaid slot 25`this abutmentrnf ge`r`23iisr so lincatedasy to' allowyfri-ie expansion nipulatingmeans'and as'loekingmeans for securing 'i v the i albutmer'it/VV finger 23". in the.4 position to. which it is set. 4Thefelutchshowninvligures Sande cany embody 'any oneoiiithe arrangements i. fclaimz;y Y Y, Y 1. .A1 centrifugal clutch comprising Vdriving and drivenV parts, centrifugal clutelir,shoes operative 'f forengagingl the dijivenzpart atra'1pre' detern'iineld ereditari' Shoes 'sheltering rai. raving. -am formations adapted toco-.actin wedgingiengagef rrnent )when "said shoesV` engage`V thefdrivenv vpart,

Ine-airis'y Aintefr-posedbetweenYsaid driving part and the Shoes adapted for'rierdegfeneasemenite:

tween said cam formations; andiadjustable lock .ingzdevio/es onvthe driving part adapted A.tol pre1 vent engagementnf "the-[clutch shoes with the driven ,part Atto-render ther-clutch inoperative,

4resistance to the circumferential movement of the shoe -1' into fil-@meinem Glutei osiprisiriadrvins me driven parts, centrifugal clutch shoes operative for engaging and' gripping the driven part at a predetermined speed, said shoesand driving part having cam formations adapted to co-actwhen said shoes are retarded owing to gripping engagement with the driven part, stops on the driving part andl the vshoes, and rcompression springs housed Ain slots formed in said shoes and ming engagement between the shoes and driven part.

3. A reversible centrifugal clutch comprising a driving part having outwardly projecting cams,

i a-driven part surrounding said driving parts, kclutch shoeslocated betweenV said driving and driven parts ladapted to engage and grip said driven part at apredeterminedspeed, cam formations .onthe front and rear of said shoes adapt- .ed to come into wedging engagement with said cams on the driving part when the shoes are retarded by engagement with .the driven part, .stops .operative between said stops for retarding camt .n thedr-ivingmember and .on-.said shoes, rods Y iixed ion thefdriving member and receivedin a circuinierential' slot formed in 4said shoes,V andr compression springs coiledrround said rods and operative' betweenV said" stops for retarding engagement Vbetween said cams andv camformations. Y

` `LA centrifugal clutchY comprisingaY driving part formed with guiding `slots 'and external c'amsfadriven `part surroundingy .said driving part, centrifugalV clutch vshoes between said parts and 'formed with cam formationadapted to coact with said'cams .on the driving `part when the vshoes lgrip the driven part, and yielding resist,-

ance means guidingly. movable in said slots and operative against said shoes for resisting the initiationof wedgingaction betweensaid cams.v

A centrifugal clutch comprisinga driving part formed y with guiding slots y, and external camsfa. driven partY surrounding said vdriving part', centrifugal clutch shoes. between saidparts and fformed with cam formations; adaptedk to cof act withsaid cams on' the driving part whenthe t shoes' grip the ldrivenn part, and vai'ixiliary cen.- Vtvrifugal elements movable Yin said slotsinythe driving, part and, operative against vsaid shoesv between said cams.

Yand?c'l'ri `ving"partv and operative forI` resisting the initiation 'offwedging action b'etweensaid cam formations. 4 Y

7.Y Centrifugal' clutch comprising driven and driving" parts, centrifugal clutch shoes operative for engaging the driven jpart at a predetermined speed, cam formations on the driving part" and cooperative`v` camV formations on ,the 'shoesA dis-A posed"circunlferentialiyv in advance of4 the vCain' formations fon the driving part, said cam formations on the driving"- partY and l shoes col-'actingin tarded on gripping thev driven part,'and'coripres sion Vsprings interposed-between sai'dlldrivingr'part and saidshcresadaptedxfori resistingthe initia.

ist'

tion of wedging action between said earn formations; 8. A reversible centrifugal clutch comprising" a driving part having` external earns, a driven part surrounding said driving part, centrifugal clutch shoesV between said parts and formed with vfront and rear cam surfaces adapted tov co-act shoes gripthe driven part, and means interposed betweenvsaidshoes and driving part and operavtive for resisting theintiation of Wedging action between said cams.

ERNESTCHARLES HATCHER. 

